Data storage and retrieval systems are used to store information provided by one or more host computer systems. Such data storage and retrieval systems receive requests to write information to one or more secondary storage devices, and requests to retrieve information from those one or more secondary storage devices. Upon receipt of a write request, the system stores information received from a host computer in a data cache. In certain implementations, a copy of that information is also stored in a nonvolatile storage device. Upon receipt of a read request, the system recalls information from the one or more secondary storage devices and moves that information to the data cache. Thus, the system is continuously moving information to and from storage devices, and to and from the data cache.
Applicants' invention includes a sector format conversion device which in the event data disposed in the data cache is written in a first sector format and the data disposed in the one or more storage devices is written in a second sector format, converts data comprising the first sector format into data comprising the second sector format. Applicants' apparatus and method preserve data integrity throughout the sector conversion process even during a power failure. In certain embodiments, Applicants' apparatus and method are compliant with the Power Failure Warning protocols under the SFF-8045 Specification.